MALIBU, Calif. » It was a cool weekday afternoon, but dozens of surfers were bobbing in the water, waiting for a wave. This was Malibu: the national symbol of surfing, adored by California wave riders for 50 years, near the famous stretch of coast where Annette Funicello and Frankie Avalon partied on the beach.

These days, Malibu is renowned for something else: a court and civic battle that has pitted surfer against surfer, environmentalist against environmentalist and City Council member against City Council member. A $7 million plan to clean up the Malibu Lagoon — its brackish waters clogged with silt and mud — has roiled a community that is more commonly identified with exclusivity and natural beauty than street protesters and smack-downs at City Council meetings.

"I don’t care if I am not recognized," Andy Lyons, a surfer, shouted at a City Council meeting recently as officials threatened to eject him if he did not sit down. "I surf there every day, and you don’t."

Environmentalists say the California State Parks cleanup project is critical to saving a lagoon that is choking on sand and silt, depleting oxygen levels and threatening native birds, fish and plant life.

But the project has alarmed some surfers, who assert that the dredging could affect the sand flow to the beach and destroy what many surfers celebrate as the best wave in the world (although that designation might not be as true as it was 20 years ago, before the last reclamation project, which many surfers think also damaged the wave).

And it has drawn strong opposition from some environmentalists upset at the prospect of bulldozers tearing through a 12-acre wetland teeming with wildlife and removing footpaths that take birdwatchers right through the heart of the lagoon.

The California Coastal Commission approved the project in October, and bulldozers were supposed to start cutting new channels June 1. But a Superior Court judge in San Francisco issued an injunction last week delaying the project until at least Sept. 1, to allow arguments in a stop-construction lawsuit filed by a coalition of environmentalists and advocates for coastal access.

"It has inspired a lot of passion, but the problem is, I think, largely because of a misunderstanding of the project," said John Sibert, the mayor of Malibu, whose Council deadlocked, 2-2, on whether to endorse the plan. "The folk who oppose the project have convinced the surfers that it’s going to destroy the break. There is no evidence of that, but it’s become dogma now, a faith-based kind of conclusion not a scientific one."

The anxiety, the mayor said, is palpable.

"A lot of my friends who are surfers are calling up and saying: ‘What’s going on? I hear they are going to get a petition out to recall you,"’ said Sibert, who, like nearly everyone involved in this dispute, is a surfer. "I said: Bring it over, I’ll sign it. We need to get the lagoon cleaned out."

The fight is a reminder of how deeply passions are felt about protecting the local coastline. Dozens of protesters showed up along the Pacific Coast Highway, which runs over the lagoon, the other morning, brandishing signs saying "Stop the Bulldozers."

"It’s a nightmare, and it’s coming down the pike," said Lyons, a third-generation surfer. "The lagoon is fine. It’s such a scam."

Other surfers said the project was being done without necessary study of what it might do to the wave.

"We’re not saying this is good or bad," said Jordan Tappis, a former professional surfer who lives in Santa Monica. "We’re saying that before the bulldozers come and change the shape of the lagoon, thorough scientific research should be done to see how it may affect the wave. Right now, it’s pure conjecture. People don’t know."

Passions have become so heated that some surfers who said they were not worried about the project declined to disclose their names and risk the wrath of other surfers. And, inevitably, there is no shortage of conspiracy theories in a part of the world where land is so valuable and developers always seem on the prowl.

"I’ve been coming here since 1964: This is one of the most beautiful spots on our coast," said Mike Forsman, 62, an amateur photographer.

He paused and lifted his camera to capture a duck — click, click, click — rising up out of the wetlands.

"Why is this happening?" he asked. "I think it’s being done because of all the people with money who want it done."

As he feasted on the rich variety of wildlife teeming around him — blue herons, brown pelicans, hummingbirds, pintails, snowy egrets, flying against the backdrop of the beach — Forsman said he could not imagine how anything could improve what he found here now.

"You can’t come in with a bulldozer and say you are going to make it better," he said.

There is almost dogmatic disagreement about the basic facts of the case. Marcia Hanscom, the director of the Wetlands Defense Fund, one of the groups that brought the suit, said there was nothing wrong with the lagoon.

"The project is not necessary — it’s really extreme, and there’s a whole ecosystem that is functioning pretty well," she said.

But the Coastal Commission and other advocates of the project point to abundant scientific evidence portraying the wetlands as endangered.

"Malibu Lagoon needs help," said Shelley Luce, the executive director of the Santa Monica Bay Restoration Commission. "It is in very bad condition. And it is one of the last lagoons left on Santa Monica Bay."

All of this has created some confusion on the beach.

"There are people who are against it, saying it’s going to make the wave worse," said Jed Pearson, 45, a Fox Sports executive who had just finished surfing. "How do you know? I’ve only surfed here for 14 or 15 years. I don’t know."

Jefferson Wagner, who has owned Zuma Jay’s surf shop for almost 35 years, said: "It’s funny seeing environmentalists going after environmentalists and surfers going after surfers. As surfers we usually go after each other in the water; everybody snakes each other in the water. Now it’s moved out here, and we are snaking everybody intellectually."